National Comics Publications and All-American Publications, two precursors to DC Comics, were formed publishing American comic books such as superhero comics starting in the 1930s. Primary Comic book anthology titles created by the company was More Fun Comics, Adventure Comics, Detective Comics, Action Comics, All-American Comics and Superman. Other companies like Quality Comics and Fawcett Comics would later be merged into DC. Quality started by introducing comic books like Feature Comics and Smash Comics.
During the period, National launched popular superhero / featured characters like Doctor Occult, Slam Bradley, Superman, Zatara, Tex Thompson, Crimson Avenger, Batman, Red Tornado and Sandman since their first appearance. Quality Comics also debuted Doll Man while Fox Feature Syndicate includes the introduction of the first Blue Beetle in Mystery Men Comics.
Superman stories debuted major supporting characters of Superman, such as Lois Lane, Jimmy Olsen, Jor-El and Lara, Jonathan and Martha Kent along with one of the earliest supervillains / Superman rogue, Ultra-Humanite. Also major fictional elements introduced in the Superman comics include the planet Krypton and the Kryptonian species, the city Metropolis and the newspaper tabloid, Daily Planet. Batman stories debuted major supporting characters of Batman such as James Gordon, Thomas and Martha Wayne along with Batman rogues like Joe Chill. Also major fictional elements introduced in the Batman comics include the fictional police department led by Gordon, the costume known as the Batsuit with weapons known as Batman's utility belt and the Batarang, an original version of two vehicles known as the Batmobile and the Batplane and the building called Wayne Manor.
- February - New Fun Comics, later retitled More Fun Comics series debuts.
- October - The characters Doctor Occult and Rose Psychic are debuted by Jerry Siegel and Joe Shuster.
- December - New Comics, then New Adventure Comics and later Adventure Comics series debuts.
- February - DC's representation of the mythological characters King Arthur and Merlin were debuted by Rafael Astarita.
- March - Detective Comics series debuts. Slam Bradley was debuted by Malcom-Wheeler Nicholson, Jerry Siegel and Joe Shuster.
- October - Quality Comics (which DC later obtains) comes to be. Feature Funnies, later retitled Feature Comics series was debuted by Quality Comics.
- All-American Publications came to be.
- June - Action Comics debuts with its historical first issue. The characters Superman / Clark Kent, George Taylor and Lois Lane are debuted by Jerry Siegel and Joe Shuster. Superman's origin, the planet Krypton and the Kryptonian species along with the Superman logo, the Daily Star along with the one of the first famous relationships in comics is debuted. The character Zatara and an recurring used name Tigress is debuted by Fred Gaudineer. The character Tex Thompson is debuted by Ken Fitch and Bernard Baily.
- October - The characters Crimson Avenger and Wing were debuted by Jim Chambers.
- November - An office boy later revealed to be Jimmy Olsen is debuted by Jerry Siegel and Joe Shuster.
- January - A Superman comic strip series was published. The characters Jor-El and Lara were debuted by Jerry Siegel and Joe Shuster.
- April - All-American Comics series is debuted. 
- May - The characters Batman and James Gordon were debuted by Bob Kane and Bill Finger. Other iconic debuts include the Batsuit and a version of the Batmobile.
- June- The character Ma Hunkel (Who later becomes Red Tornado) is debuted by Sheldon Mayer. Wayne Manor was debuted by Bob Kane.
- The character Sandman is created by Gardner Fox and Bert Christman.
- June - The character Ultra-Humanite is debuted by Jerry Siegel and Joe Shuster.
- Summer - Superman series was released. The characters Jonathan and Martha Kent are introduced by Jerry Siegel and Joe Shuster.
- July - Batman's first supervilian was debuted by Bob Kane along with Batman's utility belt being debuted by Gardner Fox.
- August - The character Blue Beetle was introduced by Charles Nicholas Wojtkoski originally by Fox Feature Syndicate. Smash Comics title by Quality Comics debuts.
- September - Metropolis takes the place of real life city Cleveland, Ohio by Jerry Siegel and Joe Shuster. Julie Madison, the Batarang, the Batgyro and Batman's second supervillain was debuted by Gardner Fox, Bob Kane and Sheldon Moldoff.
- October - The first representation of the mythological city of Atlantis is debuted by Gardner F. Fox and Fred Guardineer.
- November - Batman's origin introduces Batman’s parents (Thomas Wayne and Martha Wayne) and their killer by Bob Kane, Bill Finger, Jerry Robinson and Gardner Fox. The Daily Planet was debuted by Jerry Siegel and Joe Shuster replacing the Daily Star.
- December -The first Doll Man and supporting character who would later be Doll Girl would debut by Will Eisner.
- Fawcett Comics would be formed around sometime during 1939. Which would then be a rival of DC until later acquired by DC.
- Benton, Mike (1989). The Comic Book in America: An Illustrated History. Dallas, Texas: Taylor Publishing. pp. 17–18. ISBN 9780878336593.
- Newbold, Jamie (2018). The Forensic Comicologist: Insights from a Life in Comics. McFarland & Company. p. 127. ISBN 978-1476672670.
- Wolk, Douglas. "75 Years of the First Comic Book Superhero (It's Not Who You Think)". Time. Retrieved 23 April 2016.
- Wallace, Daniel (2010). "1930s". In Dolan, Hannah (ed.). DC Comics Year By Year A Visual Chronicle. London, United Kingdom: Dorling Kindersley. p. 13. ISBN 978-0-7566-6742-9.
With New Fun already out on the newsstands, [Malcolm] Wheeler-Nicholson didn't waste any time in adding a second title to his line. New Comics appeared in a smaller format than New Fun, one that was similar in size to what are now considered standard comic book dimensions.
- Wallace, Daniel; Dolan, Hannah, ed. (2010). "1930s". DC Comics Year By Year A Visual Chronicle. London, United Kingdom: Dorling Kindersley. p. 17. ISBN 978-0-7566-6742-9.
The launch of Detective Comics defined [Malcolm] Wheeler-Nicholson's young comics company and set it on an ascendant path within the industry...His smart business decision to partner with businessmen Harry Donenfeld and Jack Liebowitz on Detective Comics guaranteed that his company's third title would at least be solvent.CS1 maint: extra text: authors list (link)
- Steranko, Jim (1972). The Steranko History of Comics 2. Reading, PA: Supergraphics. p. 92.
- Jones, Gerard (2004). Men of Tomorrow: Geeks, Gangsters, and the Birth of the Comic Book. New York: Basic Books. ISBN 9780465036561.
- Muir, John Kenneth (July 2008). The Encyclopedia of Superheroes on Film and Television. McFarland & Co. p. 539. ISBN 978-0-7864-3755-9. Retrieved May 31, 2011.
- Wallace, Daniel (2013). Superman: The Ultimate Guide to the Man of Steel. London, United Kingdom: Dorling Kindersley. p. 126. ISBN 978-1465408754.
- Wallace, Daniel; Dolan, Hannah, ed. (2010). "1930s". DC Comics Year By Year A Visual Chronicle. London, United Kingdom: Dorling Kindersley. p. 21. ISBN 978-0-7566-6742-9.
Action Comics #6 (November 1938) The Man of Steels's future pal Jimmy Olsen made his first appearance within this issue of Action Comics, although he was identified only as an "inquisitive office-boy.CS1 maint: extra text: authors list (link)
- Wallace, Daniel; Dolan, Hannah, ed. (2010). "1930s". DC Comics Year By Year A Visual Chronicle. London, United Kingdom: Dorling Kindersley. p. 24. ISBN 978-0-7566-6742-9.
Edited by Sheldon Mayer, the title contained newspaper reprints and puzzle pages alongside original material such as Mayer's own 'Scribbly'...The features 'Hop Harrigan' and 'Red, White, and Blue' also debuted in this issue.CS1 maint: extra text: authors list (link)
- Desris, Joe (1994). "Cops, Crooks, and Creeps". The Golden Age of Batman The Greatest Covers of Detective Comics From the '30s to the '50s. New York, New York: Artabras. p. 11. ISBN 0896600467.
Gotham City's most famous detective ultimately usurped the coveted cover position with issue 35.
- The Sandman at Don Markstein's Toonopedia: "Adventure Comics #40 wasn't quite the character's first appearance, though. The 1939 issue of New York World's Fair Comics, an extra-big anthology DC put out to capitalize on the eponymous event, contained a Sandman story, and probably hit the stands a week or two before his first Adventure story (though the one in Adventure is believed to have been written and drawn earlier)." Archived from the original December 5, 2011.
- Daniels, Les. Batman: The Complete History. Chronicle Books, 1999. ISBN 0-8118-4232-0, pg. 29
- "The Blue Beetle (1939)". Don Markstein's Toonopedia. Archived from the original on April 15, 2012. Retrieved September 13, 2010.
- Greenberger, Robert (2008), "Freedom Fighters", in Dougall, Alastair (ed.), The DC Comics Encyclopedia, New York: Dorling Kindersley, p. 131, ISBN 0-7566-4119-5, OCLC 213309017
- "Thrill Comics [ashcan] #1". Grand Comics Database.